1. Field of the Invention
The present invention relates to a wireless local access network (WLAN), and more particularly, to a WLAN system management procedure and a station supporting the procedure.
2. Description of the Related Art
With the development in information communication technology, a variety of wireless communication technology has been developed. A WLAN permits wireless access to Internet in specific service areas such as home or companies or air planes by the use of portable terminals such as a personal digital assistant (PDA), a laptop computer, and a portable multimedia player (PMP) on the basis of the radio frequency technology.
These days, thanks to the increased availability of WLANs, portable terminal users such as laptop computer users are able to perform their tasks with increased mobility. For example, a user can take his laptop computer from his desk into a conference room to attend a meeting and still have access to his local network to retrieve data and have access to the Internet via one or more modems or gateways present on the local network without being tethered by a wired connection. Similarly, business travelers commonly use their portable terminals to gain access to their email accounts, to check if there is any unread email, and to read and send email.
In the initial WLAN technology, a data rate of 1 to 2 Mbps was supported by the use of frequency hopping, spread spectrum, and infrared communication using a frequency of 2.4 GHz in accordance with the IEEE 802.11. In recent years, with the development of the wireless communication technology, 54 Mbps in maximum can be supported by applying the orthogonal frequency division multiplex (OFDM) technology, etc. to the WLAN. In addition, the IEEE 802.11 has developed or is developing wireless communication technology for improvement in the quality of service (QoS), compatibility of an access point (AP) protocol, security enhancement, radio measurement or radio resource measurement, wireless access in vehicular environment, fast roaming, mesh network, inter-working with external networks, wireless network management, and the like.
The wireless network management procedure for a WLAN provides protocols relevant to the wireless network management, such as allowing a non-AP station or an access point (AP) to collect a variety of information on the wireless network or diagnosing problems of the wireless network. For example, the wireless network management procedure includes an event reporting procedure, a diagnostic reporting procedure, a presence service procedure, a base service set (BSS) transition management procedure, a flexible broadcast multicast service (FBMS) procedure, a traffic filter service (TFS) procedure, and a sleep mode procedure.
The event reporting procedure serves to diagnose states of a network in real time. The even reporting procedure in a WLAN defines a variety of events such as a transition event, a robust security network association (RSNA) event, a peer-to-peer link event, and a system log event as event request/report elements. Event request/report elements other than the system log event define various types of sub-elements. STAs supporting the event reporting procedure should store the last 5 events for the event report elements supported by the STAs after they are associated with an extended service set (ESS).
In the event reporting procedure, when a received event request frame includes requests for the transition event, the RSNA event, and/or the peer-to-peer link event and each event request includes one or more sub-elements, a requested STA contains available event report elements corresponding to a specified condition in an event report frame. On the other hand, when the specified event request does not include any sub-element, the requested STA contains all the available event report elements in the event report frame.
A station can be connected to plural stations and receive plural event request frames from one or more stations. An event request frame and an event report frame include a dialog token to identify the event request/report exchange. When receiving a new event request frame having a different dialog token before completing the process of previously received event request frames, a reporting station responses to only the latest received event request frame. Accordingly, when receiving a new event request frame before completing the process of previously received event request frames, the reporting station stops processing the present event request frame.
A network conditions between plural stations can vary and various events can occur in the stations. Accordingly, the stations can be exposed to various situations for event request and report. When a reporting station responses to only the latest received event request frame, it is not possible to properly cope with various situations and to efficiently manage a WLAN system. For example, when a station with wrong intention continuously transmits new event request frames to a reporting station, the reporting station cannot perform an event reporting procedure with another station.
Also, before completing the process of previously received event request frames, a station can receive another event request frame having the same dialog token. However, it is not clearly defined how to process the newly received event request frame. Accordingly, there is a need for a method of efficiently managing a WLAN system in various situations of a network.
On the other hand, the diagnostic procedure in the wireless network management procedure is to provide a means for diagnosing complex network issues and debugging a problem. For example, an AP or STA intending to collect information on a network or to solve a problem specifies a diagnosis type and transmits a diagnostic request frame to the associated stations or their neighboring stations. As the diagnostic request type, manufacture information, operating parameter, capability, and configuration profile are prescribed. When the diagnosis fails or the diagnosis service is not supported, the STA having received a diagnostic request frame collects or measures necessary information based on the request and transmits the collected or measured result along with a diagnostic report frame. In some cases, before completing the diagnostic report in response to the received diagnostic request frame, the reporting STA may receive another diagnostic request frame. In this way, when continuously receiving diagnostic request frames, it is important how the reporting STA should process the continuous diagnostic request frames.